Six4Three is fighting Facebook in a Californian court, where it obtained the documents via US disclosure laws.

It is reported that the cache of documents contains “significant revelations about Facebook decisions on data and privacy controls” that led to the Cambridge Analytica scandal.

This is said to include confidential emails between senior executives, and correspondence with Zuckerberg himself.

The House of Commons serjeant-at-arms reportedly went to the businessman’s hotel, and gave the CEO a final warning and a two-hour deadline to comply with the order.

When the Six4Three CEO failed to hand over the documents he was reportedly “escorted to Parliament” and warned he risked fines and imprisonment if the documents were not surrendered.

“We are in uncharted territory,” said MP Damian Collins. “This is an unprecedented move but it’s an unprecedented situation. We’ve failed to get answers from Facebook and we believe the documents contain information of very high public interest.”

Collins said the reluctance of Zuckerberg to testify, plus misleading testimony from Schroepfer, had forced MPs to explore other options for gathering information about Facebook operations.

Collins also later told the BBC that he believed the documents were “highly relevant” to his inquiry.

Unhappy Facebook

But Facebook is unhappy with the move and has demanded the documents return.

“The materials obtained by the DCMS committee are subject to a protective order of the San Mateo Superior Court restricting their disclosure,” Facebook told the Observer.

“We have asked the DCMS committee to refrain from reviewing them and to return them to counsel or to Facebook,” it said.

Six4Three is suing Facebook in the United States after it invested $250,000 in an app. It alleged the cache of documents shows Facebook was not only aware of the implications of its privacy policy, but actively exploited them, intentionally creating and effectively flagging up the loophole that Cambridge Analytica used to collect data.

Collins and his committee had been following this US case, and when the businessman entered British jurisdiction, Parliament moved quickly to secure the documents.